Supervisory indication of carrier current transmitter



July' 2, 1935. 1. L. WOODWORTH 2,006,975

I SUPERVISORY INDICATION 0F CARRIER CURRENT TRANSMITTER Filed Oct. 21. 1950 Fig. L

SUPERVISORY CONTROL EQUIPMENT- Inventor: John 1.. WooclWoTth,

H is Att1- neg.

gized in response to relay 2 to operate a contact member 38 over a bank of contacts to which the windings of switches 9, I5, and II are connected. Thus, after operation of relay 2 the motor 8 becomes energized to drive the generator "I, and motor 29 becomes energized to operate the contact member 30 over its bank of contacts. The switches 9, I0, and II are then closed in succession, each of the switches being closed for a proper interval suflicient to cause the street lamps associated with the respective phase of the power system to be turned on. Thus after closure of each switch it is opened and the next switch closed. When the last switch I i has been closed for its proper interval, the operation of the transmitter is interrupted. The same operation occurs when relay 3 is operated but switches 9, I and II are closed each for a longer interval thereby to cause the street lights to be turned 0fi-,1

It will of course be understood that the transmitter I may be of any desired type and that the elements indicated in the rectangle representing this transmitter are shown only for the purpose of indicating conventionally, and as simply as possible, on the drawing, the general nature of apparatus which may be employed, a more preferred form-of apparatus being fully explained in Patent 1,869,185 above referred to.

My present invention relates to means whereby a proper answer back signal may be transmitted through the supervisory equipment 4 only when the desired remote control or signal impulses have been transmitted over all of the different outgoing circuits or phases of the power system and whereby upon failure of the equipment to transmitthe desired signal impulse over any one or more of the diiferent outgoing circuits no answer back indication is produced.

To this'end a number of carrier current re- 'ceivers'IZ, I3 and I4 are provided, these receivers being associated with the different outgoing cir- "cuits or phases of the power system. These receivers may be of any suitable construction adapted selectively to respond to the transmitted signals. Thus for example these receivers may be of the type shown in my co-pending application, Serial No. 443,909, filed April 12, 1930, U. S.

- Patent No. 1,816,755, granted July 28, 1931, for

selective control systems, a portion of which is l shown inFig. 2 of the drawing. Each of these receivers comprises a bimetallic conducting member I5 which may be supplied with an energizing current through means not shown in response to received carrier current from the corresponding phase of the power system. The receiver in- -cludes an armature I6 which is pivoted at one end I! and the opposite end of which rests on the upper end of the bimetallic member I5. To

the armature I6 is attached a contact carrying "member I8 which reciprocates between the stationary contacts I9 and 20. Thus when the L armature is in its upper position the contact I8 engages the contact I9.

of the bimetallic strip I5, it deflects to the left,

When, due to heating it permits the armature I6 to be attracted by the horseshoe magnet 2I and causes the contact I8-to be operated to its lower position and into Thus, when carrier current is received for an interval having the duration necessary to cause the street lamps to be turned on, the bimetallic member I5 is energized and deflects just sufiiciently to reu please the armature I 6 and (1'76 7 permit it to be attracted to its lower osition. r

at the remote station.

Cooperating with the thermostat I5 and the contact carrying member I8 is a small bell lever member 22 having an arm 23 which normally projects downward and to the left of the bimetallic strip I5 and a second arm 24 which projects to the right between the armature I6 and the contact carrying member I8, this lever being pivoted at a central point in such a way that it is freely suspended in the position shown in the drawing.

When the long carrier impulse which is utilized to turn thestreet lamps off is received the bimetallic strip I5 is deflected proportionately further to the left and accordingly it engages the arm 23 of the bell lever and causes it to swing clockwise about its pivot. When the bimetallic strip has about reached the extent of its defiection it passes the lever 23 which falls behind it. Then, when the carrier impulse is interrupted the bimetallic strip tends to cool and to return to its initial position. As it does so, it engages the opposite side of the lever 23 and rocks the lever about its pivot in a counter clockwise direction thereby forcing the arm 24 upward until it engages the contact carrying member I3 and forms it into its upper position. As it does so the bimetallic strip I5 slips past the lever 23 and under the armature I6 thereby holding the armature I5 in its upper position.

Thus each of the receivers I2, I3, and I4 of Fig; 1 have two stationary contacts I9 and and an armature reciprocal therebetween. All of the contacts 20 are connected together and to one side of a resistance 25 and similarly all the contacts I9 are connected together and to the opposite side of resistance 25. A suitable source of potential 26, such as a battery, is connected between the midpoint on resistance 25 and all of the armatures I8. In parallel with resistance 25 is connected the winding of polarized answer back relay 21.

Thus when all of the armatures I8 engage the stationary contacts 20, the battery 26 is connected across the lower portion of resistance 25 and the polarized relay is energized in such a direction as to actuate its armature toward the right. When all the armatures engage their respective contacts I9 the source of potential 26 is connected across the upper portion of resistance 25 and the relay 2'! is energized in the opposite direction and accordingly actuates its armature to the left. The supervisory equipment is of course arranged to transmit signals in accordance, with the position of the armature of the answer back relay 21.

Thus if the transmitter I functions properly and transmits a signal over each of the different outgoing circuits of proper duration to turn the street lamps either on or oif a corresponding answer back indication will be trans-;

operate properly, it will be observed that arma-i ture I8 of receiver I2 will then be in engagement with its contact I9 whereas .armature I8 of receivers I3 and I4 will engage their contacts 20. The winding of relay 2'! is then short-circuited and the relay deenergized. The relay will therefore remain in the position at which it last operated and accordingly no return signal is given. Thus the operator is informed that some fault has occurred in the operation of the equipment While I have particularly mentioned impulses of long and short duration and have shown in part a selective receiver to respond to such impulses, it will of course be understood that I do not wish to be limited thereto since my invention is equally operable to systems utilizing any other type of selective signals, it being necessary only to utilize a different and well known type of receiver in connection therewith.

Thus while I have shown a particular embodiment of my invention, it will be understood that this embodiment is capable of different modifications and that I contemplate by the appended claims to cover any modifications which fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In combination, a plurality of circuits, means for automatically applying predetermined signals to each of said circuits, an answer back signal device, and means selectively responsive to said predetermined signals applied to each of said circuits to operate said answer back signal device when the same predetermined signal has been applied to all of said circuits, said means including means for normally preventing operation of said answer back device upon failure of said predetermined signal to be applied to any one of said circuits.

2. In combination, a transmitter having a plurality of output circuits, means for controlling said transmitter from a remote point to.

cause it selectively to apply predetermined signals to each of said output circuits in succession, and answer back signal means for transmitting an indication to said remote point, said last means including means for transmitting said indication only when the same predetermined signals have been appliedto all of said circuits.

3. In combination, a plurality of signal circuits, a transmitter arranged to transmit different predetermined signals, means for selectively controlling said transmitter to cause it to apply any of said signals to each of said circuits, selective means responsive to said signals connected to each of said circuits, and means controlled by said last means for transmitting an indication in accordance with the signal transmitted, said last means including means for normally preventing the transmission of said indication except when the same signal has been applied to all of said circuits.

4. In combination, a plurality of signal circuits, a-transmitter arranged to transmit either of two different signals, each of said signals being transmitted over each of said circuits, a polarized answer back relay having a resistance connected in shunt with the winding thereof, a source of potential and means connected to each of said signal circuits selectively to connect said source of potential between the midpoint on said resistance and one of the ends thereof dependent upon the signal transmitted, all of said means being arranged in response, to the same signal to connect said source between the midpoint and the same end of said resistance whereby said relay is energized with current having polarity determined in accordance with the signal transmitted and is deenergized in response to failure of either of said signals to be applied to all of said circuits. 7

JOHN L. WOODWORTH. 

